Light bulb with adjustable light output

ABSTRACT

A light bulb includes a base, a light source and a light guide having opposed major surfaces and a light input edge that receives light from the light source, the light propagating along the light guide by total internal reflection and the light guide including a light output region on one of the major surfaces. An optical adjuster has a first region having a light modifying characteristic and a second region. The optical adjuster and light output region are variably positionable relative to one another to selectively apportion light emitted from the light output region between the first region and the second region, the light apportioned to the first region being modified by the light modifying characteristic thereof so that light output from the light bulb is modified based on relative positioning of the optical adjuster and the light guide.

RELATED APPLICATION DATA

This application claims the benefit of U.S. Provisional PatentApplication Nos. 61/453,745 (filed Mar. 17, 2011), 61/454,228 (filedMar. 18, 2011), and 61/597,867 (filed Feb. 13, 2012), the disclosures ofwhich are incorporated herein by reference in their entireties.

BACKGROUND

Energy efficiency has become an area of interest for energy consumingdevices. One class of energy consuming devices is lighting devices.Light emitting diodes (LEDs) show promise as energy efficient lightsources for lighting devices. But control over color and light outputdistribution is an issue for lighting devices that use LEDs or similarlight sources.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of a light bulb representing an exemplarylighting assembly with adjustable light output, where a portion of ahousing of the light bulb is cut away to show a light source assembly;

FIG. 2 is a schematic view of a lighting fixture representing anotherexemplary lighting assembly with adjustable light output;

FIGS. 3-5 are exploded views showing part of an embodiment of a lightingassembly having adjustable light output;

FIGS. 6A-6C are exploded views showing parts of embodiments of alighting assembly having adjustable light output;

FIG. 7 is a schematic view showing part of an embodiment of a lightingassembly having adjustable light output;

FIG. 8A is a schematic view showing part of an embodiment of a lightingassembly having adjustable light output;

FIGS. 8B and 8C are partial cross-sectional views of the lightingassembly of FIG. 8A when configured to direct light from the lightingassembly in respective directions;

FIG. 9 is a schematic view showing part of an embodiment of a lightingassembly having adjustable light output;

FIG. 10 is an exploded view of another exemplary lighting assembly withadjustable light output;

FIG. 11 is a plan view of a light adjuster for the lighting assembly ofFIG. 10; and

FIG. 12 is a plan view of another light adjuster for the lightingassembly of FIG. 10.

DETAILED DESCRIPTION

Embodiments will now be described with reference to the drawings,wherein like reference numerals are used to refer to like elementsthroughout. The figures are not necessarily to scale. Features that aredescribed and/or illustrated with respect to one embodiment may be usedin the same way or in a similar way in one or more other embodimentsand/or in combination with or instead of the features of the otherembodiments.

Aspects of this disclosure relate to a lighting assembly. As illustratedin FIG. 1, one type of lighting assembly 10 is a light bulb 12. Asillustrated in FIG. 2, another type of lighting assembly 10 is alighting fixture 14.

As described in greater detail below, the lighting assembly includes alight guide to propagate light by total internal reflection. The lightguide has a light output region on a major surface thereof. The lightingassembly also includes an optical adjuster having a major surfacejuxtaposed with and conforming in surface contour to the major surfaceof the light guide. The optical adjuster has a first region and a secondregion, the first region having a light modifying characteristic. Theoptical adjuster and the light output region of the light guide arevariably positionable relative to one another to selectively apportionlight emitted from the light output region between the first region andthe second region. In this way, the light apportioned to the firstregion is modified by the light modifying characteristic thereof so thata characteristic of the light output from the lighting assembly ismodified based on the relative positioning of the optical adjuster andthe light output region.

In the case of the light bulb 12, the light bulb 12 additionallyincludes a base configured to mechanically mount the light bulb andreceive electrical power.

With additional reference to FIG. 3, the lighting assembly 10, whether abulb 12, a lighting fixture 14, or another type of lighting device, willbe described in greater detail. The lighting assembly 10 includes alight source assembly 16. The light source assembly 16 includes one ormore light sources 18. Each light source 18 is typically embodied as oneor more solid-state devices. In one embodiment, the light sources 18 aremounted to a printed circuit board (PCB) 19 (FIG. 1).

Exemplary light sources 18 include solid state devices such as LEDs,laser diodes, and organic LEDs (OLEDs). In an embodiment where the lightsource 18 is one or more LEDs, the LEDs may be top-fire LEDs orside-fire LEDs, and may be broad spectrum LEDs (e.g., emit white light)or LEDs that emit light of a desired color or spectrum (e.g., red light,green light, blue light, or ultraviolet light). In one embodiment, thelight source 18 emits light with no operably-effective intensity atwavelengths greater than 500 nanometers (nm) (i.e., the light source 18emits light at wavelengths that are predominantly less than 500 nm).Although not specifically illustrated, the light source assembly 16 alsoincludes structural components (e.g., PCB 19) to retain the lightsources 18. The light source assembly 16 may additionally include:circuitry, power supply and/or electronics for controlling and drivingthe light sources 18, a heat sink, and any other appropriate components.

The lighting assembly 10 also includes a light guide 20. Light from thelight sources 18 is input into the light guide 20. The light guide 20 isa solid article made from, for example, acrylic, polycarbonate, glass,or another appropriate material. The light guide 20 also may be amulti-layer light guide having two or more layers. The light guide 20has opposed major surfaces 22 and 24. Depending on the configuration ofthe light guide 20, the light guide has at least one edge. For instance,in a case where the light guide 20 is shaped like a dome, the lightguide has one edge. In a case where the light guide 20 is a hollowcylinder (e.g., as shown in FIGS. 1 and 8A), is frustroconical (e.g., asshown in FIG. 7), is a frustrated pyramid, is a dome with a hole cut atthe dome's apex, or another similar shape, the light guide has twoopposed edges. Other light guide 20 shapes for either a light bulb 12 ora lighting fixture 14 are possible, such as a globe or a shapeapproximating the bulbous shape of a conventional incandescent bulb. Inone embodiment, a light bulb configuration or a lighting fixtureconfiguration may be established using planar or curved light guides 20that are arranged in a three-dimensional geometric (e.g., polygonal)configuration. In the case where the light guide 20 is rectangular(e.g., as shown in FIGS. 2 and 3), the light guide 20 has four edges.Other geometries for the light guide 20 result in a corresponding numberof edges. Depending on the geometry of the light guide 20, each edge mayfollow a straight path or a curved path, and adjacent edges may meet ata vertex or join in a curve.

One of the light guide edges serves as a light input edge 26. In someembodiments, the light input edge 26 is an external edge of the lightguide 20 (e.g., as shown in FIGS. 1-5 and 7-9). In another embodiment,the light input edge 26 is an internal edge of the light guide 20, whichis an edge completely surrounded by the light guide 20 and is usually anedge of a hole 48 that extends between the major surfaces of the lightguide 20 (e.g., as shown in FIG. 6A). Light output from the lightsources 18 is directed toward the light input edge 26. Additionaloptical elements (e.g., lenses, reflectors, etc.) may be present toassist in inputting the light into the light guide 20. Once input intothe light guide 20, the light propagates through the light guide bytotal internal reflection (TIR) at the opposed major surfaces 22, 24.For purposes of this disclosure, any light input surface of the lightguide 20 is considered a light input edge, even if it is located on oneof the major surfaces 22, 24 or forms part of a light turning and/orhomogenizing structure to introduce light between the major surfaces 22,24 in a manner that allows the light to propagate along the light guide20 by total internal reflection at the major surfaces 22, 24.

Length and width dimensions of each of the major surfaces 22, 24 aremuch greater than, typically ten or more times greater than, thethickness of the light guide 20. For instance, in the rectangularembodiment shown in FIG. 2, the length (measured from the light inputedge 26 to an opposite edge distal the light input edge 26) and thewidth (measured along the light input edge 26) of the light guide 20 areboth much greater than the thickness of the light guide 20. Thethickness is the dimension of the light guide 20 in a directionorthogonal to the major surfaces. The thickness of the light guide 20may be, for example, about 0.1 millimeters (mm) to about 10 mm. Thelight guide 20 may be rigid or flexible.

The light guide 20 includes light extracting elements 27 in or on atleast one of the major surfaces 22, 24. Light extracting elements 27that are in or on a major surface 22, 24 will be referred to as being“at” the major surface 22, 24. Each light extracting element 27functions to disrupt the total internal reflection of the propagatinglight that is incident on the light extracting element 27. In oneembodiment, the light extracting elements 27 reflect light toward theopposing major surface so that the light exits the light guide 20through the opposing major surface. Alternatively, the light extractingelements 27 transmit light through the light extracting elements 27 andout of the major surface 22, 24 of the light guide 20 having the lightextracting elements 27. In another embodiment, both of these types oflight extracting elements 27 are present. In yet another embodiment, thelight extracting elements 27 reflect some of the light and refract theremainder of the light incident thereon. Therefore, the light extractingelements 27 are configured to extract light from one or both of themajor surfaces 22, 24.

A light output region 28 may occupy part or all of one or both of themajor surfaces 22, 24. In the example shown in FIG. 3, multipleinstances of light output region 28 occupy part of the major surface 22.In the example shown in FIG. 9, a single light output region 28 occupiesthe entire major surfaces 22, 24.

In the example shown in FIG. 3, the light extracting elements 27 arearranged in a pattern to form a number of distinct and spaced-apartlight output regions 28, each of which emits light from one or both ofthe major surfaces 22, 24. For purposes of illustration, each lightoutput region 28 is denoted in the appended figures by hatching shown onthe portion of the major surface 22, 24 through which light is emitted.

The light extracting elements 27 for each light output region 28 may beat one or both of the major surface 22, 24 through which light isemitted, or at the opposite major surface 22, 24. Light guides havingsuch light extracting elements 27 are typically formed by a process suchas stamping, molding, embossing, extruding, laser etching, chemicaletching, or another suitable process. Light extracting elements 27 mayalso be produced by depositing elements of curable material on the lightguide 20 and curing the deposited material using heat, UV-light or otherradiation. The curable material can be deposited by a process such asprinting, ink jet printing, screen printing, or another suitableprocess. Alternatively, the light extracting elements 27 may be insidethe light guide between the major surfaces 22, 24 (e.g., the lightextracting elements 27 may be light redirecting particles and/or voidsdisposed in the light guide).

The light extracting elements 27 are configured to extract light in adefined intensity profile, such as uniform intensity, and/or a definedlight ray angle distribution over the light output region 28. Usingvariations in the light extracting elements 27, each light output region28 need not have the same intensity profile and/or light ray angledistribution. Intensity profile refers to the variation of intensitywith position within a light-emitting region (such as light outputregion 28). Light ray angle distribution refers to the variation ofintensity with ray angle (typically a solid angle) of light emitted froma light-emitting region (such as light output region 28).

Exemplary light extracting elements 27 include light-scatteringelements, which are typically features of indistinct shape or surfacetexture, such as printed features, ink jet printed features,selectively-deposited features, chemically etched features, laser etchedfeatures, and so forth. Other exemplary light extracting elements 27include features of well-defined shape, such as V-grooves, lenticulargrooves, and features of well-defined shape that are small relative tothe linear dimensions of the major surfaces 22, 24, which are sometimesreferred to as micro-optical elements. The smaller of the length andwidth of a micro-optical element is less than one-tenth of the longer ofthe length and width of the light guide 20, and the larger of the lengthand width of the micro-optical element is less than one-half of thesmaller of the length and width of the light guide. The length and widthof the micro-optical element are measured in a plane parallel to themajor surface 22, 24 of the light guide 20 for flat light guides 20 oralong a surface contour for non-flat light guides 20.

Micro-optical elements are shaped to predictably reflect light orpredictably refract light. However, one or more of the surfaces of themicro-optical elements may be modified, such as roughened, to produce asecondary effect on light output. Exemplary micro-optical elements aredescribed in U.S. Pat. No. 6,752,505 and, for the sake of brevity, willnot be described in detail in this disclosure. The micro-opticalelements may vary in one or more of size, shape, depth or height,density, orientation, slope angle, or index of refraction such that adesired light output from the light guide 20 is achieved over thecorresponding light output region 28.

Although not specifically illustrated in connection with each lightguide 20 shown in the appended drawing figures, each light guide 20includes light extracting elements 27 in a configuration to achieve thedescribed light extracting functions.

As indicated, the lighting assembly 10 includes an optical adjuster 30.The optical adjuster 30 has opposed major surfaces 32 and 34. One of themajor surfaces, e.g., major surface 34 in the appended figures, of theoptical adjuster 30 faces one of the major surfaces, e.g., major surface22 in the appended figures, of the light guide 20. The major surface 34is juxtaposed with and conforms in surface contour to the facing majorsurface 22 of the light guide 20. In the embodiment where the lightguide 20 is planar (e.g., as shown by example in FIGS. 2 and 3), theoptical adjuster 30 is planar and located adjacent one of the majorsurface 22. Depending on the orientation of the lighting assembly 10,the optical adjuster 30 may be located above, below, or to the side ofthe light guide 20. In another example in which the light guide 20 isconfigured as a hollow cylinder such as shown in FIG. 1, the opticaladjuster 30 also is a hollow cylinder and is located inside the lightguide 20 or outside the light guide 20 in a coaxial manner. In theembodiment of FIGS. 1 and 8A, the optical adjuster 30 is coaxiallylocated outside the light guide 20 with the major surface 34 conformingto the major surface 22. In embodiments with other geometries, theoptical adjuster 30 has a different shape than the light guide 20, butthe facing surfaces of the optical adjuster 30 and the light guide 20conform to each other.

The major surface 34 of the optical adjuster 30 that faces the lightguide 20 is separated from the major surface 22 so that it does notdisrupt the total internal reflection within the light guide 20. In oneembodiment, one or more spacers 35 (e.g., FIG. 7) are present betweenthe optical adjuster 30 and the light guide 20 to assist in maintaininga desired gap between the optical adjuster 30 and the light guide 20.

One or more additional optical adjusters (e.g., a film with an opticalcharacteristic) may be located in tandem with the optical adjuster 30and the light guide 20. Exemplary additional optical adjusters will bedescribed in more detail below with reference to FIGS. 6B and 6C.

For each light output region 28 of the light guide 20, the opticaladjuster 30 has two or more optical adjuster regions. In the embodimentof FIG. 3, for example, the optical adjuster 30 has a first region 36and a second region 38 for each light output region 28. There may bethree, four or some other number of optical adjuster regions for eachlight output region 28, and each light output region 28 need not havethe same number of optical adjuster regions.

At least one of the regions 36, 38 of the optical adjuster 30 has anoptical modifying characteristic. For instance, in the illustratedembodiment of FIG. 3, each first region 36 has an optical modifyingcharacteristic denoted by hatching shown on the corresponding portion ofthe optical adjuster 30. In the illustrated embodiment, each firstregion 36 has the same optical modifying characteristic, but this neednot be the case and/or one or more of the first regions 36 need not haveany optical modifying characteristic.

An optical modifying characteristic is indicated by an effect that theregion has on light that is incident on the region. Exemplary opticalmodifying characteristics include reflective, diffusive, lightredirecting, polarizing, reflective polarizing, intensity reducing,wavelength shifting and color attenuating. Wavelength shifting is usedherein to refer to a process in which a material absorbs light atcertain wavelengths, and reemits the light at one or more differentwavelengths. Wavelength shifting may be achieved using a phosphormaterial, a luminescent material, a luminescent nanomaterial such as aquantum dot material, a conjugated polymer material, an organicfluorescent dye, an organic phosphorescent dye, lanthanide-doped garnet,or the like. Color attenuating may be achieved using color filteringmaterial. For purposes of this description, the lack of an opticalmodifying characteristic is considered a region of the optical adjuster30 that is specularly transmissive, even though specularly transmissivematerial refracts light that passes through the material at a non-zeroangle of incidence. Each second region 38 also may have an opticalmodifying characteristic or may be specularly transmissive. In theillustrated embodiments, the change in optical characteristic from thefirst region 36 to the second region 38 is abrupt. In other embodiments,the transition between the first region 36 and the second region 38 maybe gradual. A gradual transition may be appropriate where at least oneof the regions 36, 38 has an optical modifying characteristic related tointensity reducing, wavelength shifting or color attenuating, but alsomay be used in other situations. The effect that the regions 36, 38 haveon light that is output from the lighting assembly 10 will be describedin greater detail below.

With additional reference to FIGS. 4 and 5, the optical adjuster 30 andthe light guide 20 are moveable relative to each other. In the exampleshown, the optical adjuster 30 axially translates (e.g., slides)relative to the light guide 20 so that the amount of overlap between thefirst region 36 and the light output region 28 is adjustable and acorresponding change occurs in the amount of overlap between the secondregion 38 and the light output region 28. In the example shown in FIG.5, the amount of overlap has been adjusted so that the light outputregion 28 aligns with the first region 36 so that all or nearly alllight that is emitted from the light output region 28 is incident on thefirst region 36 and is modified by the first region's light modifyingcharacteristic. In the example shown in FIG. 3, the amount of overlaphas been adjusted so that the light output region 28 aligns with thesecond region 38 so that all or nearly all light that is emitted fromthe light output region 28 is incident on the second region 38 and ismodified by the second region's light modifying characteristic, if any.In the example shown in FIG. 4, a portion of the first region 36 and aportion of the second region 38 align with the light output region 28 sothat a portion of the light emitted by the light output region 28 isincident on the first region 36 and is modified by the first region'slight modifying characteristic, and a portion of the light emitted bythe light output region 28 is incident on the second region 38 and ismodified by the second region's light modifying characteristic, if any.In FIGS. 3-5, the amount of overlap is illustrated using broken linesthat show the position of edges of the first regions 36 relative to thelight output regions 28. In one embodiment, the surface area and theshape of the first region 36 and the surface area and the shape of thesecond region 38 are the same as a surface area and a shape of the lightoutput region 28. But the surface areas and shapes of one or both of theregions 36, 38 need not be the same as the surface area and shape of thelight output region 28.

The lighting assembly 10 holds one of the optical adjuster 30 or thelight guide 20 in a fixed position while allowing movement of the otherof the optical adjuster 30 or the light guide 20. Alternatively, boththe optical adjuster 30 and the light guide 20 are moveable. Therelative movement may allow for adjustment of the amount of overlap ofthe first region 36 with the light output region 28, and correspondinglythe amount of overlap of the second region 38 with the light outputregion 28, in any selective apportionment between two extremes.Alternatively, movement may be made in increments to adjust the amountof overlap among defined locations.

The movement allows for selectively apportioning light that is emittedfrom the light output region 28 between the amount of light that isincident on the first region 36 and the amount of light that is incidenton the second region 38. Light that is incident on the first region 36is modified by the light modifying characteristic of the first region36. Similarly, if the second region 38 has a light modifyingcharacteristic, light that is incident on the second region 38 ismodified by the light modifying characteristic of the second region 38.Otherwise, the light that is incident on the second region 38 is outputfrom the second region with no operably-effective modification. In thismanner, light output from the lighting assembly 10 is modified based onrelative positioning of the optical adjuster 30 and the light outputregion 28 of the light guide 20.

In one embodiment, the relative positioning is varied manually by auser. In the example shown in FIG. 1, the lighting assembly 10 includesa user-manipulable mechanism 42 that moves one or both of the lightguide 20 and the optical adjuster 30 relative to the other to vary therelative positioning of the light guide 20 (and hence the light outputregion 28) and the optical adjuster 30. As shown in FIG. 1, the lightguide 20 is fixed relative to a housing 40 and the optical adjuster 30is rotatably moveable relative thereto by the manual application offorce to the mechanism 42. In the embodiment of FIG. 1, the mechanism 42is a member that is secured to the optical adjuster 30 and slides over aportion of the housing 40 of the light bulb 12. In one embodiment, theamount of movement is limited by stops (not illustrated). Othermanually-operated mechanisms are possible. For instance, other types ofsliders may be employed or a turnable knob may act on the moveablecomponent through a gear or drive train. In other embodiments, themechanism 42 is motorized to move one or both of the light guide 20 andthe optical adjuster 30 relative to the other. The motorized mechanismmay be controlled by a control assembly (not shown) to adjust lightoutput based on user input, feedback from sensors, or a triggeringevent. In still other embodiments, there is no mechanism 42 and theadjustment is made by applying a positioning force, which in the case ofthe exemplary cylinder is torque, directly to the moveable one of theoptical adjuster 30 and the light guide 20.

Once positioned, the relative positioning of the light guide 20 and theoptical adjuster 30 remains unchanged until the user or control assemblyvaries the relative positioning. Since constant motion of the lightguide 20 relative to the optical adjuster 30 is not contemplated duringoperation of the lighting assembly 10, the range of movement of thelight guide 20 and/or the optical adjuster 30 may be limited. The rangeof movement may be limited to back-and-forth sliding that moves thefirst region 36 in and out of alignment with the light output region 28,rather than allowing infinite movement of the light guide 20 or theoptical adjuster 30 in one direction.

A visual indicator may be present to provide the user with an indicationof the modification applied to the light output of the lighting assembly10. In the illustrated embodiment of FIG. 1, for example, markings 44are present on the optical adjuster 30 and align relative to a pointer46 on the housing to provide this indication.

FIG. 6A illustrates another example of the light guide 20 and theoptical adjuster 30. In this example, the light guide 20 and the opticaladjuster 30 are disk-shaped, but other shapes are possible. A hole 48extends through the light guide 20 between the major surfaces 22, 24 andthe edge of the hole 48 provides the light input edge 26 through whichlight is input into the light guide 20. In the embodiment of FIG. 6A,the relative positioning between the light output regions 28 of thelight guide 20 and the first regions 36 of the optical adjuster 30 isvaried by rotation of one or both of the light guide 20 and the opticaladjuster 30 relative to the other. The optical adjuster 30 has acontiguous portion that establishes the second region 38 in which thespaced-apart first regions 36 are defined. In the illustratedembodiment, the first regions 36 and the light output regions 28 arecongruent. The optical adjuster 30 of the illustrated embodiment has ahole for mounting to a spindle or other mechanism (not shown) to allowmovement thereof. Other than having a different type of movement to varythe relative positioning (rotation instead of translation), theembodiment of FIG. 6A achieves modification of the light output in thesame manner as the embodiment of FIGS. 3-5. Therefore, for the sake ofbrevity, modification of the light output by varying the relativepositioning of the light guide 20 and the optical adjuster 30 to varythe amount of overlap between the first and second regions 36, 38 andthe light output regions 28 will not be described.

In an example, the first regions 36 are transmissive but configured withan additional optical modifying characteristic and the second region 38is reflective. Varying the relative positioning of the optical adjuster30 and the light guide 20 modifies the direction in which the light isemitted from the lighting assembly 10. In one example of the relativepositioning of the optical adjuster 30 and the light guide 20, thetransmissive first regions 36 are aligned with the light output regions28. In this example, the light output from the light output regions 28and incident on the transmissive first regions 36 is modified by theoptical characteristics of the first regions 36 and is output from thelighting assembly 10 in a direction away from the major surface 22. Inanother example of the relative positioning of the optical adjuster 30and the light guide 20, the reflective second region 38 is aligned withthe light output regions 28. In this example, light output from thelight output regions 28 and incident on the second region 38 isreflected back into the light guide 20 through the respective lightoutput region 28 and passes through the light guide 20 and out the majorsurface 24. This light is output from the lighting assembly 10 in adirection away from the major surface 24, i.e., in a direction oppositethat of the light that was output with the light output regions 28aligned with the first regions 36. The light extracting elements 27 ofthe light guide 20 also may be configured so that light is additionallyoutput from the major surface 24 by disruption of the total internalreflection of the light propagating in the light guide 20.

In a variation of the lighting assembly 10 of FIG. 6A, half (by area) ofthe optical adjuster 30 is specularly transmissive and half (by area) ofthe optical adjuster 30 is specularly reflective (e.g., half of theoptical adjuster 30 provides the transmissive first regions 36contiguously or non-contiguously, and half of the optical adjuster 30provides the reflective second region 38 correspondingly contiguously ornon-contiguously). Half of the major surface 22 provides the lightoutput regions 28 correspondingly contiguously or non-contiguously.Depending upon the relative positioning of light guide 20 and opticaladjuster 30, the light output of the lighting assembly 10 can beadjusted to provide a light output distribution anywhere between all ofthe light output from the light output regions 28 being directed out ofthe lighting assembly 10 in a direction away from the major surface 22and all of the light output from the light output regions 28 beingdirected out of the lighting assembly 10 in a direction away from themajor surface 24.

In the example shown in FIG. 6B, the light guide 20 and the opticaladjuster 30 are similar to those of FIG. 6A, but a second opticaladjuster 50 is located between the light guide 20 and the first opticaladjuster 30, specifically between major surfaces 22 and 34. The secondoptical adjuster 50 has a contiguous portion that provides a secondregion 54 in which spaced-apart first regions 52 are defined. In someembodiments, the light extracting elements 27 of the light guide 20 areconfigured so that light output regions 28 are at the major surface 22.In the illustrated embodiment, the first regions 52 are congruent withthe light output regions 28 of the light guide 20. In an example, thesecond region 54 is reflective and the spaced-apart first regions 52 arespecularly transmissive or the first regions 52 are openings defined inthe contiguous second region 54. The second optical adjuster 50 modifiesa characteristic of the light before it becomes incident on the firstoptical adjuster 30 in accordance with the optical modifyingcharacteristics of the first regions 52 and the second region 54 of thesecond optical adjuster and the relative positioning of the secondoptical adjuster and the light output regions 28 of the light guide 20.The first optical adjuster 30 then further modifies the characteristic(or modifies a different characteristic) of the light output by thelighting assembly 10 in accordance with the optical modifyingcharacteristics of the first regions 36 and the second region 38 of thefirst optical adjuster 30 and the relative positioning of the firstoptical adjuster 30, the second optical adjuster 50, and the lightoutput regions 28 of the light guide 20. Thus, the light output from thelighting assembly 10 is modified by various combinations of the opticalmodifying characteristics of the optical adjusters 30 and 50 dependingon relative positioning between the light output regions 28 of the lightguide 20 and the optical adjusters 30, 50.

In the illustrated embodiments of FIGS. 6A and 6B, the light outputregions 28 each are in the exemplary shape of an oval and have acorresponding first regions 52 in the shape of the exemplary oval in thesecond optical adjuster 50 and a corresponding first regions 36 in theshape of the exemplary oval in optical adjuster 30. Other shapes arepossible, such as sectors, trapezoids, squares, triangles, circles, etc.In one embodiment, the angular offset of the first regions 52 from oneanother on the second optical adjuster 50 matches the angular offset ofthe first regions 36 from one another on the optical adjuster 30 so thatthe same amount of overlap is achieved between each corresponding pairof the first region 52 and the first region 36. But this need not be thecase so that different amounts of overlap are achieved between eachcorresponding pair of the first region 52 and the first region 36. Inone embodiment, the angular offset of the light output regions 28 fromone another matches the angular offset of the first regions 36 from oneanother on the optical adjuster 30 and/or matches the angular offset ofthe first regions 52 from one another on the second optical adjuster 50,but this need not be the case Also, the light guide 20 and opticaladjusters 30, 50 need not be circular (e.g., they may be rectangular)and need not be planar (e.g., they may be hollow cylinders, or hollowand frustroconical).

In the embodiment illustrated in FIG. 6B, the optical adjusters 30, 50are configured to rotate through a confined range of rotation relativeto the light guide 20 and/or each other. Additionally or alternatively,the light guide 20 is configured to rotate through a confined range ofrotation. For this purpose, one or both of optical adjusters 30, 50 ismounted on a spindle (not illustrated) or bearing assembly (notillustrated), rotation about which varies the relative positioning ofthe light guide 20, the optical adjuster 30, and the additional opticaladjuster 50.

In the above-described embodiments, the light output regions 28 of thelight guide 20 are defined by respective regions of light extractingelements 27 at one or both of the major surfaces 22, 24 of the lightguide. In other embodiments, the light extracting elements 27 cover allor nearly all of one or both major surfaces 22, 24 of the light guide,and the light emission regions are defined by an auxiliary opticaladjuster. With reference to FIG. 6C, another embodiment of a lightingassembly 10 employing the optical adjuster 30 and a light guide havingan auxiliary optical adjuster 51 is illustrated.

In the embodiment of FIG. 6C, the light extracting elements 27 of thelight guide 20 are configured so that light is output from all or nearlyall of the major surface 22 of the light guide 20. The auxiliary opticaladjuster 51 has first regions 53 that are transmissive (e.g., specularlytransmissive), and second regions 55 that are reflective. Each firstregion 53 of the auxiliary optical adjuster 51 defines a respectivelight output region 28 of light guide 20. The light output regions 28projected onto the major surface 22 of the light guide 20 are denoted bybroken lines in FIG. 6C. In the example shown, the first regions 53 andsecond regions 55 are equal in area, but this need not be the case.

In the example shown, the auxiliary optical adjuster 51 is a solidarticle juxtaposed with and independent of the light guide 20. The firstregions 53 of the auxiliary optical adjuster 51 may be provided byopenings in a contiguous second region 55, or by spaces absent ofmaterial forming the auxiliary optical adjuster 51 betweennon-contiguous second regions 55. Embodying the auxiliary opticaladjuster 51 as a solid article separate from the light guide 20 allowsthe positions of the light output regions 28 defined by the firstregions 53 of the auxiliary optical adjuster 51 to be varied by varyingthe position of the auxiliary optical adjuster 51 and without varyingthe position of the light guide 20. Alternatively, the auxiliary opticaladjuster 51 embodied as a solid article may be fixed in positionrelative to the light guide 20, in which case, the positions of thelight output regions 28 are varied by varying the position of the lightguide 20 and auxiliary optical adjuster 51 together. In other examples,the auxiliary light guide 51 is integral with the light guide 20. Forexample, sectors of reflective material may be deposited on or affixedto one of the major surfaces of the light guide 20 to provide thereflective second regions 55 of the auxiliary optical adjuster 51, withthe uncovered portions providing the transmissive first regions 53. Inexamples in which the auxiliary light guide 51 is integral with thelight guide 20, the position of the light guide 20 is varied to vary thepositions of the light output regions 28 defined by the first regions 53of the auxiliary optical adjuster 51. In some embodiments, the firstregions 53 of the auxiliary optical adjuster 51 are transmissive andhave an additional optical characteristic (e.g., color attenuating).

In the embodiment of FIG. 6C, the first regions 36 of the opticaladjuster 30 are transmissive (e.g., specularly transmissive ortransmissive with an additional optical characteristic, such as colorattenuating or diffusive) and the second regions 38 of the first opticaladjuster 30 are reflective. The light output from the light guide 20 andincident on the reflective second regions 55 of the auxiliary opticaladjuster 51 is reflected back into the light guide 20, and the reflectedlight exits the light guide 20 through the major surface 24. Lightoutput from the light guide 20 and transmitted through the first regions53 of the second optical adjuster 50 is incident on the optical adjuster30. The relative positioning of the optical adjuster 30 and the lightoutput regions 28 (defined by the first regions of the auxiliary opticaladjuster 50) apportions the light exiting the light output regions 28between the transmissive first portions 36 and the reflective secondportions 38 of the optical adjuster 30. The portion of the light exitingthe light output regions 28 and incident on the first regions 36 of theoptical adjuster 30 is output from the lighting assembly 10 in adirection away from the major surface 22 of the light guide 20. But theportion of the light exiting the light output regions 28 and incident onthe reflective second regions 38 of the optical adjuster 30 is reflectedback through the light output regions 28 (defined by the transmissivefirst regions 53 of the auxiliary optical adjuster 51), enters the lightguide 20 through the major surface 22, passes through the light guide 20and is output from the lighting assembly in a direction away from themajor surface 24 of the light guide 20, i.e., in a direction oppositethat in which the portion of the light incident on the transmissivefirst portions 36 is output. Therefore, the light output from thelighting assembly 10 is selectively apportioned between light that isoutput in the direction away from the major surface 22 and light that isdirected away from the major surface 24. The apportionment depends onthe overlap between the light output regions 28 of the light guide(defined by the transmissive first regions 53 of the auxiliary opticaladjuster 51) and the transmissive first regions 36 of the opticaladjuster 30, with the apportionment depending on the relativepositioning of the optical adjuster 30 and the light output regions 28of the light guide 20 defined by the auxiliary optical adjuster 51. Thelight extracting elements 27 of the light guide 20 also may beconfigured so that light is additionally output from the major surface24 of the light guide 20.

FIG. 7 illustrates an example of another embodiment of a lightingassembly 10 having an adjustable light output. In this example, thelight guide 20 and the optical adjuster 30 are hollow, frustroconicaland coaxial, and the optical adjuster 30 is located radially inward fromthe light guide 20. In this embodiment, as with the embodiments wherethe light guide 20 and the optical adjuster 30 are cylindrical, theamount of overlap between the first region 36 and the light outputregion 28 is controlled by the relative positioning of the opticaladjuster 30 and the light output region 28 of the light guide 20 inrotation.

In some embodiments, the light guide 20 supports the optical adjuster30. In other embodiments the optical adjuster supports the light guide.In the example shown in FIG. 7, for example, hanger members 58 suspendthe light guide 20 from the optical adjuster 30. Other supportconfigurations are possible. In an example, the housing 40 of the lightbulb 12 (FIG. 1), or a housing 59 (FIG. 2) of the lighting fixture 14supports both the optical adjuster 30 and the light guide 20 in a mannerthat retains the optical adjuster 30 and the light guide 20 within thelighting assembly 10. Other exemplary supports include poles, hooks,hubs, bearings, mating slots and ridges, mating indents and detents,etc. In one embodiment, the optical adjuster 30 is replaceable withanother optical adjuster 30 having different optical characteristics topermit more light modification options.

A number of embodiments of the lighting assembly 10 described above withreference to FIGS. 1-7 and configured for various applications will nowbe described.

Some applications call for the lighting assembly 10 to output light withspecific light ray angle distributions. Embodiments configured for usein such applications modify the light ray angle distribution of thelight output from the light output region 28 of the light guide 20 toprovide output light having a light ray angle distribution suitable forthe application. In an example, the first region 36 has optical elementsconfigured as light redirecting elements. In this case, the light outputfrom the light output region 28 of the light guide 20 is incident on thefirst region 36 and is redirected in accordance with the lightredirecting characteristics of the light redirecting elements in thefirst region 36. In one variation of this example, the second region 38has a second light modifying characteristic (e.g., a diffusivecharacteristic) such that the light received from the light outputregion 28 is modified to have a light ray angle distribution broaderthan that of the light output by the first region 36. In anothervariation, the second region 38 has light redirecting elements thatredirect the light received from the light output region 28 differentlyfrom the light redirecting elements of the first region 36 such thatlight ray angle distribution of the light redirected by the secondregion 38 has a peak intensity at a different ray angle and/or has abroader or a narrower peak than that of the light redirected by thefirst region 36.

In a configuration of lighting assembly 10 suitable for anotherapplication, the lighting assembly 10 modifies the direction of thelight output by the lighting assembly. The first region 36 is reflectiveand the second region 38 is transmissive (e.g., specularly transmissive,diffusive, or light redirecting). In this manner, the direction of thelight output by the lighting assembly 10 is controlled by the relativepositioning of the light output region 28 of the light guide 20 and theoptical adjuster 30. Similar to the example described above withreference to FIG. 6A, when the output light is to be output from themajor surface 22 having the light output region 28, the transmissivesecond region 38 is aligned with the light output region 28 so that thesecond region 38 transmits the light output from the light output region28. When the output light is to be output from the other major surface24, the reflective first region 36 is aligned with the light outputregion 28 so that the first region 36 reflects the light output fromlight output region 28 back toward and through the light guide 20. Whenthe output light is to be output from both the major surfaces 22, 24,the first and second regions 36, 38 are positioned so that a portion ofeach partially overlaps the light output region 28. With thispositioning, part of the light from the light output region 28 istransmitted by the second region 38 and part (typically the remainder)of the light from the light output region 28 is reflected by the firstregion 36. The amount of overlap of the respective regions 36, 38 withthe light output region 28 determines the apportioning of the light fromthe light output region 28 between the two directions.

In some embodiments, an optical component (not shown) that does not moverelative to the light guide 20 is adjacent the light guide 20 on theside opposite the optical adjuster 30 to modify the light reflected bythe reflective first region 36. The optical component may be reflective,diffusive, light redirecting, polarizing, reflective polarizing,intensity reducing, wavelength shifting, or color attenuating, forexample.

In a configuration of lighting assembly 10 suitable for still otherexemplary applications, the lighting assembly 10 modifies the color ofthe light output from the lighting assembly 10. For example, in anembodiment of a portable lamp, such as a lantern, the first region 36and the second region 38 are specularly transmissive and the firstregion 36 additionally includes a color filter. In an example,positioning the second region 38 in alignment with the light outputregion 28 causes white light to be output from the lighting assembly 10,whereas positioning the first region 36 in alignment with the lightoutput region 28 causes colored light to be output from the lightingassembly 10.

The color of the light output by the lighting assembly 10 may be changedusing a color filter layer on or as part of the optical adjuster 30 inone or both regions 36, 38 thereof, a color filtering materialcomposition of the optical adjuster in one or both regions 36, 38thereof, a dichroic filter on or as part of the optical adjuster in oneor both regions 36, 38 thereof, or a wavelength shifting material on oras part of the optical adjuster in one or both regions 36, 38 thereof.In one example, the lighting assembly 10 is configured to change colortemperature of the light output. Many LED light sources 18 emit light ina range of wavelengths intended to achieve a corresponding colortemperature. However, within batches of LEDs having the same nominalcolor temperature, there is variation of color temperature from LED toLED. Also, sometimes broad-spectrum LEDs (e.g., “white light” LEDs) orgroups of tri-color LEDs (e.g., a red LED, a blue LED and a green LEDwhose outputs combine to produce white light) do not produce a colortemperature that is desirable to a user or appropriate for a certainlighting application. To modify the color temperature of the lightoutput from the lighting assembly 10, the first region 36, and possiblythe second region 38, may be used. For instance, the first region 36 maymodify the light output to be warmer (either or both of more red andless blue) and the second region 38 may modify the light output to becooler (either or both of more blue and less red).

Some embodiments are configured to allow a user to adjust the colortemperature of light output from the lighting assembly 10 in order toachieve a desired color temperature. Other embodiments are configured toallow a manufacturer of the lighting assembly 10 to adjust the colortemperature of light output from the lighting assembly 10 to compensatefor different color temperatures associated with different lots of lightsources 18. This allows the lighting assembly manufacturer to source abroader range of light sources 18 from one or more suppliers and stillmanufacture lighting assemblies with a defined, consistent colortemperature.

In some embodiments, the relative positioning of the light output regionof the light guide 20 and the optical adjuster 30 is varied by themanufacturer of the lighting assembly 10 until the output light has adefined characteristic (e.g., a defined color temperature is obtained).The relative positioning is then fixed by the manufacturer, and thelighting assembly 10 is configured in a manner to minimize the abilityof a user of the lighting assembly 10 to further vary the relativepositioning. In other embodiments, the user has the ability to vary therelative positioning.

Configurations of the light assembly 10 suitable for other applicationswill be apparent based on using any of the above-noted light modifyingcharacteristics for the first region 36, or based on using anycombination of the above-noted light modifying characteristics for thefirst region 36, the second region 38, and any additional regions of theoptical adjuster 30 that are capable of overlapping with the lightoutput region 28 of the light guide 20.

With additional reference to FIGS. 8A and 9, some embodiments of thelighting assembly 10 include the optical adjuster 30, sometimes referredto as the first optical adjuster 30, and a second optical adjuster 60.Each of the optical adjusters 30, 60 is configured in accordance withthe foregoing embodiments so that each optical adjuster 30, 60 has arespective first region 36, 62 having a respective light modifyingcharacteristic and a respective second region 38, 64 that has arespective light modifying characteristic or is specularly transmissive.The light modifying characteristics of the first regions 36, 62 and/or,if applicable, the second regions 38, 64 need not be the same.

The light output region 28 of the light guide 20, the first opticaladjuster 30 and the second optical adjuster 60 are variably positionablerelative to one another. In one embodiment, the relative positioning ofthe light guide 20 and the second optical adjuster 60 is independent ofthe relative positioning of the light guide 20 and the first opticaladjuster 30. In another embodiment, the relative positioning of thelight guide 20 and second optical adjuster 60 is dependent on therelative positioning of the light guide 20 and the first opticaladjuster 30. In some embodiments, one or both of the optical adjusters30, 60 are variably positionable relative to the light output region 28of the light guide 20.

In the illustrated embodiments, the first and second optical adjusters30, 60 are on opposite sides of the light guide 20 so that one majorsurface 34 of the first optical adjuster 30 faces one major surface 22of the light guide 20 and one major surface 66 of the second opticaladjuster 60 faces the other major surface 24 of the light guide 20. Theother major surface 68 of the second optical adjuster 60 faces away fromthe light guide 20. Additionally, the major surface 66 is juxtaposedwith, and conforms in surface contour to, the facing major surface 24 ofthe light guide 20. In other embodiments, both the first opticaladjuster 30 and the second optical adjuster 60 are located on the sameside of the light guide 20.

In an embodiment where there are two optical adjusters 30, 60 onopposite sides of the light guide 20, light output from the light outputregion 28 is incident on the second optical adjuster 60. In thisembodiment, the second region 64 of the second optical adjuster 60 isreflective to reflect the incident light back through the light guide20. The amount of reflected light depends on the amount of overlap ofthe reflective second region 64 with the light emitting region 28. Thereflected light, after exiting the major surface 22 is incident on thefirst optical adjuster 30. Light incident on the first optical adjuster30 is apportioned between the first and second regions 36, 38 dependingon the overlap of these regions with the reflected light. The lightmodifying characteristics of the first and/or second regions 36, 38modify the light respectively incident on these regions 36, 38, therebymodifying the overall characteristics of the light output from thelighting assembly 10.

An exemplary embodiment of the lighting assembly 10 shown in FIG. 8A hasa light output selectable from a narrow light ray angle distribution, abroad light ray angle distribution, and an intermediate light ray angledistribution, depending on the relative positioning of the light outputregion 28 of the light guide 20 and the optical adjusters 30, 60. Theintermediate light ray angle distribution is a light ray angledistribution between the narrow light ray angle distribution and thebroad light ray angle distribution, and results from a combination ofthe two depending on the apportioning of the light output from the lightguide between regions of the optical adjusters.

Operation of the embodiment shown in FIG. 8A will be described next withadditional reference to FIGS. 8B and 8C. The first region 62 of thesecond optical adjuster 60 is transmissive, the second region 64 of thesecond optical adjuster 60 is reflective, and the first and secondregions 36, 38 of the first optical adjuster 30 are transmissive andhave respective light redirecting characteristics. Additionally, thelight output region 28 is on the major surface 24 of the light guide 20facing the second optical adjuster 60, and the light guide 20 isconfigured to have minimal light output from the major surface 22.

As represented by the light ray 72 in FIG. 8B, the light extractingelements 27 for the light output region 28 are configured to outputlight from the light output region 28 at low ray angles. Low ray anglesare ray angles directed away from the light source 18 and arepredominantly at less than 45 degrees relative to the major surface 24of the light guide 20. As indicated, the first region 62 of the secondoptical adjuster 60 is transmissive. In an example in which the firstregion 62 is specularly transmissive, the light from the light outputregion 28 exits the lighting assembly 10 at low ray angles and has anarrow light ray angle distribution. In an example in which the firstregion 62 is light redirecting and is configured to turn the light toeven lower ray angles, the light ray angle distribution has a peak at alower ray angle than in the example in which the first region 62 isspecularly transmissive. Additionally, the peak may be narrower.

As represented by the light ray 74 in FIG. 8C, when the reflectivesecond region 64 of the second optical adjuster 60 overlaps the lightoutput region 28, the second region 64 reflects the light output fromthe light output region. The reflected light re-enters the major surface24, passes through the light guide 20, exits the major surface 22, andis incident on the first optical adjuster 30. The first optical adjuster30 is transmissive, so that light exits the lighting assembly 10 in adirection away from the major surface 22 of the light guide 20. Toprovide a desired amount of adjustability to the characteristics of thereflected light, the first region 36 may be one of specularlytransmissive (e.g., so that the first region outputs light with the samelight ray angle distribution as that of the light incident on theoptical adjuster 30), diffusive (e.g., so that the first region 36outputs light with a broader ray angle distribution than that of thelight incident on optical adjuster 30), or light-redirecting so that thefirst region 36 outputs light with a light ray angle distribution whosepeak is at a different angle from that of the light incident on opticaladjuster 30.

In an embodiment, the second region 38 of the first optical adjuster 30has a different transmissive characteristic than the first region 36 ofthe first optical adjuster 30. By varying the relative positioning ofall three of the light output region 28 of the light guide 20, the firstoptical adjuster 30, and the second optical adjuster 60, the lightoutput from the lighting assembly 10 is modifiable among a light outputwith a low and/or narrow ray angle distribution (e.g., light output byway of the first region 62 of the second optical adjuster 60), lightoutput dependent on the optical characteristic of the first region 36 ofthe optical adjuster 30, and light output dependent on the opticalcharacteristic of the second region 38 of the optical adjuster 30.

With reference to all of the figures, and FIG. 9 in particular, thelight extracting elements 27 of the light guide 20 can be configured toprovide two light output regions 28 and 76, respectively, on theopposite major surfaces 22, 24 of the light guide 20. The light outputregions 28 and 76 may be aligned with each other or may be offsetrelative to each other; the light output regions 28 and 76 may outputlight with the same light ray angle distribution or different light rayangle distributions. Additionally or alternatively, the light outputregions 28 and 76 may output light with the same or different intensityprofiles. Light output from the respective light output regions 28, 76is independently modified by respective optical adjusters 30, 60 toprovide light with characteristics suitable for illuminating respectiveillumination surfaces.

Returning to FIG. 1, additional details regarding the lighting assembly10 when embodied as the light bulb 12 will be described. The light bulb12 includes a base 78. The illustrated base 78 is an Edison base, butother types of bases 78 may be used, including any commercially-standardbase or proprietary base used for mechanically securing an incandescentbulb, a fluorescent bulb, a compact fluorescent bulb (CFL), a halogenbulb, a high intensity discharge (HID) bulb, an arc lamp, or any othertype of bulb into a lamp, a lighting fixture, a flashlight, a light bulbsocket, etc., and/or for supplying electricity thereto. The light bulb12 typically further includes a heat sink 80 that dissipates heatgenerated by the light sources 18. The heat sink 80 of the illustratedembodiment forms part of the housing 40. Parts of the light bulb 12,such as the light guide 20 and the optical adjuster 30, are describedabove with reference to FIGS. 3, 4, 5, 6A-6C, 7, 8A-8C and 9.

References herein to a “light bulb” are meant to broadly encompasslight-producing devices that fit into and engage any of various fixturesfor mechanically mounting the light-producing device and for providingelectrical power thereto. Examples of such fixtures include, withoutlimitation, screw-in fixtures for engaging an Edison light bulb base, abayonet fixture for engaging a bayonet light bulb base, or a bi-pinfixture for engaging a bi-pin light bulb base. Thus the term “lightbulb,” by itself, does not provide any limitation on the shape of thelight-producing device, or the mechanism by which light is produced fromelectric power. Also, the light bulb need not have an enclosed envelopeforming an environment for light generation. The light bulb may conformto American National Standards Institute (ANSI) or other standards forelectric lamps, but the light bulb does not necessarily have to havethis conformance.

Returning to FIG. 2, additional details regarding the lighting fixture14 will be described. The lighting fixture 14 may be a hanging light (asshown), a ceiling light (e.g., an assembly to fit in a drop-down ceilingor secure flush to a ceiling), a wall sconce, a table lamp, a tasklight, or any other illumination device. The lighting fixture includesthe housing 59 for retaining the light source assembly 16, the lightguide 20 and the optical adjuster 30. The housing 59 may retain or mayserve as a heat sink. In some embodiments, the lighting fixture 14includes a mechanism 82 (e.g., a chain or wire in the case of a hanginglight, clips or fasteners in the case of a ceiling light or wall sconce,etc.) to mechanically secure the lighting assembly to a retainingstructure (e.g., a ceiling, a wall, etc.). In other embodiments, themechanism 82 is a stand and/or base assembly to allow the lightingfixture 14 to function as a floor lamp, table lamp, task lamp, etc.Electrical power is supplied to the lighting fixture through appropriateconductors, which in some cases may form part of or pass through themechanism 82. Parts of the lighting fixture 14, such as the light guide20 and the optical adjuster 30, are described above with reference toFIGS. 3, 4, 5, 6A-6C, 7, 8A-8C and 9.

With additional reference to FIG. 10, illustrated is another exemplarylighting assembly 10 configured as a light bulb 12. The light guide 20in the illustrated embodiment is cylindrical and has a distal edge 84 atan end of the light guide 20 opposite the light input edge 26. Similarto FIG. 1, a portion of the housing 40 of the light bulb 12 of FIG. 10is shown broken away to depict a portion of the light input edge 26 andthe light source assembly 16 with one or more light sources 18 andprinted circuit board 19. Light that propagates through the light guide20 and is not extracted by light extracting elements 27 at the majorsurfaces 22 or 24 will become incident on the edge 84.

The distal edge 84 has first regions 86 that are circumferentiallyinterleaved with second regions 88 along the distal edge 84. The secondregions 88 have an optical modifying characteristic. In one embodiment,the optical modifying characteristic of the second regions 88 isreflective. The reflective optical modifying characteristic for thesecond regions 88 is accomplished using a reflective coating, forexample. In this embodiment, the first regions 86 of the distal edge 84are transmissive. In some embodiments, the first regions 86 aretransmissive and have an additional optical characteristic (e.g., colorattenuating or diffusive). In other embodiments, the first regions 86and/or the second regions 88 have other optical modifyingcharacteristics, such as diffusive, light redirecting, polarizing,reflective polarizing, intensity reducing, wavelength shifting and colorattenuating.

In the embodiment where the second regions 88 are reflective and thefirst regions 86 are transmissive, light incident on the second regions88 is reflected and propagates in the light guide 20 by total internalreflection toward the light input edge 26. Light incident on the firstregions 86 with an angle less than the critical angle for total internalreflection exits the edge 84. For purposes of illustration, the secondregions 88 are shown hatched in FIG. 10.

The light bulb 12 of FIG. 10 includes an optical adjuster 90. Withadditional reference to FIG. 11, a plan view of the side of the opticaladjuster 90 that faces the distal edge 84 of the light guide 20 isshown. In one embodiment, the optical adjuster 90 is a ring that is madeof metal, plastic, or other suitable material. The optical adjuster 90of the illustrated embodiment includes an inner side wall 94 that fitswithin the inner diameter of the light guide 20 (e.g., conforms to theinner major surface 22 of the light guide 20), an outer side wall 96that fits over the outer diameter of the light guide 20 (e.g., conformsto the outer major surface 24 of the light guide 20), and an annulus 92that spans between the inner side wall 94 and the outer side wall 96.The annulus 92 has a surface 93 (FIG. 11) that is juxtaposed with thedistal edge 84 when the optical adjuster 90 is installed on the lightguide 20.

The annulus 92 of the optical adjuster 90 has first adjuster regions 98that are circumferentially interleaved with second adjuster regions 100around the optical adjuster 90. For purposes of illustration, the firstadjuster regions 98 are shown hatched in the FIG. 11. In one embodiment,the first adjuster regions 98 are reflective and the second adjusterregions 100 are transmissive. The first adjuster regions 98 may be madereflective by adding a reflective coating to portions of the surface 93of the annulus 92 that form the first regions 98 of the optical adjuster90 or, depending on the material of the optical adjuster 90, polishingportions of the surface 93 of the annulus 92 that form the first regions98 of the optical adjuster 90. In one embodiment, the optical adjuster90 is made of a reflective material, such as a white plastic, or aplastic having a reflective coating, and the second adjuster regions 100are defined by openings in the optical adjuster 90 that allow light topass. In other embodiments, the second adjuster regions 100 are madefrom transmissive material. In other embodiments, the first adjusterregions 98 and/or the second adjuster regions 100 have other opticalmodifying characteristics, such as diffusive, light redirecting,polarizing, reflective polarizing, intensity reducing, wavelengthshifting and color attenuating.

The optical adjuster 90 and the light guide 20 are moveable relative toeach other. In the example shown, the optical adjuster 90 rotatesrelative to the light guide 20 so that the amount of overlap between thefirst adjuster regions 98 of the optical adjuster 90 and the firstregions 86 of the edge 84 is controlled by the relative positioning ofthe optical adjuster 90 and the light guide 20. The optical adjuster 90is secured to the light guide 20 by any appropriate means, such as oneor more detents (not shown) on the optical adjuster 90 that are receivedby one or more corresponding indents (not shown) of the light guide 20.In some embodiments, the optical adjuster 90 and the light guide 20 areconfigured to rotate through a confined range of rotation relative toeach other (e.g., the amount of relative movement may be limited to adesired number of degrees of rotational travel). In one embodiment, therange of motion allows for relative positioning corresponding to fulloverlap of the first regions 98 of the optical adjuster 90 with thefirst regions 86 of the distal edge 84 and relative positioningcorresponding to full overlap of the first adjuster regions 98 of theoptical adjuster 90 with the second regions 88 of the distal edge 84.

In one embodiment, there are a reflective first adjuster region 98 and atransmissive second adjuster region 100 of the optical adjuster 90 foreach transmissive first region 86 of the edge 84. Also, the amount ofoverlap between each reflective first adjuster region 98 of the opticaladjuster 90 and the respective transmissive first region 86 of the edge84 is adjustable from no overlap to complete overlap, including anyselective apportionment therebetween. A corresponding change in theamount of overlap between each transmissive second adjuster region 100of the optical adjuster 90 and the transmissive first regions 86 of theedge 84 will occur. In one embodiment, when there is no overlap betweenthe reflective first adjuster regions 98 of the optical adjuster 90 andthe transmissive first region 86 of the edge 84, light exiting the lightguide 20 through the transmissive first region 86 of the edge 84 willpass through the transmissive second adjuster region 100 of the opticaladjuster 90 and continue in a direction away from the light bulb 12. Inthis manner, the light energy that is output by the first region 86 ofthe edge 84 and reflected by the first adjuster region 98 of the opticaladjuster 90 is controllable. Light that is reflected by the reflectivefirst adjuster regions 98 of the optical adjuster 90 typically re-entersthe light guide 20 through the respective first regions 86 of the edge84 and propagates in the light guide 20 by total internal reflectiontoward the light input edge 26. At least some of this light is extractedby the light extracting elements 27 at at least one of the majorsurfaces 22, 24 of the light guide 20, as described below.

In a variation of the lighting assembly 10 of FIGS. 10 and 11, thereflective second portions 88 occupy half of the area of the edge 84,and anywhere from none of the light transmitted by the transmissivefirst portions 86 of the edge 84 to all of the light transmitted by thetransmissive first portions 86 of the edge 84 is reflected by thereflective adjuster portions 98 of the optical adjuster 90. In anembodiment in which the light incident on the edge 84 is equally dividedbetween the reflective and transmissive portions of the edge 84,anywhere from half of the light to all of the light incident on the edge84 is reflected back toward the light input edge 26 depending on therelative positioning of the optical adjuster 90 and the light guide 20.

With additional reference to FIG. 12, another embodiment of the opticaladjuster 10 is shown. In FIG. 12 a plan view of the side of the opticaladjuster 90 that faces the distal edge 84 of the light guide 20 isshown. The optical adjuster 90 of FIG. 12 includes an inner side wall 94that fits within the inner diameter of the light guide 20 (e.g.,conforms to the inner major surface 22 of the light guide 20), an outerside wall 96 that fits over the outer diameter of the light guide 20(e.g., conforms to the outer major surface 24 of the light guide 20),and an annulus 92 that spans between the inner side wall 94 and theouter side wall 96. The annulus 92 has a surface 93 that is juxtaposedwith the distal edge 84 when the optical adjuster 90 is installed on thelight guide 20. In one embodiment, there are a reflective first adjusterregion 98 and a transmissive second adjuster region 100 of the opticaladjuster 90 for each transmissive first region 86 of the edge 84. In oneembodiment, the transmissive second adjuster regions 100 are openings inthe annulus 92 and, in another embodiment, the transmissive secondadjuster regions 100 are made of material transmissive to the lightoutput from the light guide 20 through the distal edge 84.

The size of the first adjuster region 98 in the radial direction (and,correspondingly, the size of the second adjuster region 100 in theradial direction) changes with circumferential position around theoptical adjuster 90. Therefore, the relationship between rotation of theoptical adjuster 90 and the effect on light output through the distaledge 84 by the first adjuster region 98 will be different from that ofthe example described above with reference to FIG. 11. In someembodiments, the taper of first adjuster region 98 is non-linear toprovide a non-linear relationship between the rotation of the opticaladjuster 90 and the effect on light output through the distal edge 84.Also, in the illustrated embodiment, the first adjuster regions 92 arecircumferentially longer than either of the first regions 86 or thesecond regions 88. Therefore, in the illustrated embodiment where theregions 86 and 88 are each the same size and uniformly distributedaround the distal edge 84, at least a portion of each first adjusterregion 98 will overlap one of the first regions 86 and a remainder ofthe first adjuster region 98 will over a neighboring one of the secondregions 88. In other embodiments, the size and shape of the firstadjuster regions 98 are the same as the size and shape of the firstregions 86.

The light energy incident on the edge 84 depends on the light energythat is extracted through major surfaces 22, 24 by the light extractingelements 27. In one embodiment, about five to ten percent of the lightentering the light guide at the light input edge 26 is incident on theedge 84. In one embodiment, the light extracting elements 27 areconfigured to extract light that has been reflected at the edge 84 or atthe optical adjuster 90 as the reflected light propagates toward thelight input edge 26. The light extracting elements 27 extract the lightpropagating away from the light input edge 26 and the light propagatingtoward the light input edge 26 with different directional properties.Thus, adjusting the optical adjuster 90 adjusts the overall light rayangle distribution of the light extracted from the light guide 20.

The modifiable light output of the lighting assembly 10 of FIGS. 10through 12 may be used for any of the above-described applications.Also, at the time of the writing of this disclosure, ENERGY STAR®program specifications for A19 light bulbs describe that about fivepercent of the light flux from the bulb's light source should be outputat light ray angles ranging from 135° to 180° to an axis that extendsfrom the base to the top of the light bulb. The optical adjuster 90enables the lighting assembly 10 to have a range of light energyemissions towards the base, including an ENERGY STAR-compliant emissiontoward the base, depending on alignment between the optical adjuster 90and the edge 84.

In this disclosure, the phrase “one of” followed by a list is intendedto mean the elements of the list in the alternative. For example, “oneof A, B and C” means A or B or C. The phrase “at least one of” followedby a list is intended to mean one or more of the elements of the list inthe alternative. For example, “at least one of A, B and C” means A or Bor C or (A and B) or (A and C) or (B and C) or (A and B and C).

1. A light bulb, comprising: a base configured to mechanically mount thelight bulb and receive electrical power; a light source electricallycoupled to the base; a light guide having opposed major surfaces and alight input edge, the light guide coupled to the base and arranged toreceive light from the light source at the light input edge, the lightpropagating along the light guide by total internal reflection, thelight guide comprising a light output region on one of the majorsurfaces; and an optical adjuster having a major surface juxtaposed withand conforming to one of the major surfaces of the light guide, theoptical adjuster having a first region and a second region, the firstregion having a light modifying characteristic, the optical adjuster andlight output region variably positionable relative to one another toselectively apportion light emitted from the light output region betweenthe first region and the second region, the light apportioned to thefirst region being modified by the light modifying characteristicthereof so that a characteristic of the light output from the light bulbis modified based on relative positioning of the optical adjuster andthe light output region.
 2. The light bulb of claim 1, furthercomprising a heat sink thermally coupled to the light source.
 3. Thelight bulb of claim 1, wherein the characteristic of the light outputfrom the light bulb that is modified is spectrum.
 4. The light bulb ofclaim 1, wherein the characteristic of the light output from the lightbulb that is modified is color temperature.
 5. The light bulb of claim1, wherein the characteristic of the light output from the light bulbthat is modified is light ray angle distribution.
 6. The light bulb ofclaim 1, wherein the light apportioned to the first region is emittedfrom the light output region in a first area of the light output regionthat is overlapped by the first region and the light apportioned to thesecond region is emitted from the light output region in a second areaof the light output region that is overlapped by the second region, theamount of overlap of the first region and the second region with thelight output region depending on the relative positioning of the opticaladjuster and the light guide.
 7. The light bulb of claim 6, wherein thefirst region, the second region and the light output region have thesame size and shape.
 8. The light bulb of claim 6, wherein the firstregion and the light output region have the same size and shape.
 9. Thelight bulb of claim 1, further comprising a manually-operated mechanismto move at least one of the light guide and the optical adjusterrelative to the other.
 10. The light bulb of claim 1, further comprisinga motorized mechanism to move at least one of the light guide and theoptical adjuster relative to the other.
 11. The light bulb of claim 1,wherein the light source is a solid-state light source.
 12. The lightbulb of claim 1, wherein the light guide additionally comprises a regionof light extracting elements at at least one of the major surfaces ofthe light guide to define the light output region.
 13. The light bulb ofclaim 12, wherein the light extracting elements are light-scatteringelements.
 14. The light bulb of claim 12, wherein the light extractingelements have well-defined shapes.
 15. The light bulb of claim 12,wherein the light extracting elements are micro-optical elements. 16.The light bulb of claim 1, wherein the light guide additionallycomprises: an auxiliary optical adjuster adjacent one of the majorsurfaces and configured to define the light output region; and lightextracting elements at at least one of the major surfaces of the lightguide, the light extracting elements configured to extract the lightfrom the light guide in a region of the one of the major surfaces of thelight guide adjacent the auxiliary optical adjuster.
 17. The light bulbof claim 16, wherein the region from which the light is extracted islarger than the light output region
 18. The light bulb of claim 1,wherein the light guide and the optical adjuster are planar.
 19. Thelight bulb of claim 1, wherein the light guide is curved and the opticaladjuster conforms to a curvature of the light guide.
 20. The light bulbof claim 19, wherein the light guide and the optical adjuster arecoaxial hollow cylinders.
 21. The light bulb of claim 19, wherein thelight guide and the optical adjuster are hollow, frustroconical andcoaxial.
 22. The light bulb of claim 1, wherein the second region isreflective to reflect light incident on the second region back throughthe light guide.
 23. The light bulb of claim 22, further comprising adiffusive optical component adjacent the light guide on a side of thelight guide opposite the optical adjuster to diffuse the reflectedlight.
 24. The light bulb of claim 22, additionally comprising anoptical component on which the reflected light that exits the lightguide is incident, the optical component being at least one of lightredirecting, polarizing, reflective polarizing, intensity reducing,wavelength shifting and color attenuating.
 25. The light bulb of claim1, wherein the light bulb further comprises an additional opticaladjuster having a major surface juxtaposed with and conforming to theother of the major surfaces of the light guide, the additional opticaladjuster having a first region and a second region, the first region ofthe additional optical adjuster having a light modifying characteristic,the additional optical adjuster and light guide variably positionablerelative to one another to selectively apportion light output by thelight guide and incident on the additional optical adjuster between thefirst region of the additional optical adjuster and the second region ofthe additional optical adjuster, the light apportioned to the firstregion of the additional optical adjuster being modified by the lightmodifying characteristic thereof so that a characteristic of the lightoutput from the light bulb is also modified based on relativepositioning of the additional optical adjuster and the light guide. 26.The light bulb of claim 25, wherein the light guide additionallycomprises a second light output region on the other of the majorsurfaces.
 27. The light bulb of claim 25, wherein the relativepositioning of the additional optical adjuster and the light guide isindependent of the relative positioning of the optical adjuster and thelight guide.
 28. The light bulb of claim 25, wherein the relativepositioning of the additional optical adjuster and the light guide isdependent on the relative positioning of the optical adjuster and thelight guide.
 29. The light bulb of claim 25, wherein the additionaloptical adjuster is a hollow cylinder coaxial with the light guide. 30.The light bulb of claim 25, wherein the additional optical adjuster ishollow, frustroconical and coaxial with the light guide.
 31. The lightbulb of claim 1, wherein the light modifying characteristic of the firstregion is at least one of reflective, diffusive, light redirecting,polarizing, reflective polarizing, intensity reducing, wavelengthshifting and color attenuating.
 32. The light bulb of claim 31, whereinthe second region is specularly transmissive or has a light modifyingcharacteristic different than the first region and that is at least oneof reflective, diffusive, light redirecting, polarizing, reflectivepolarizing, intensity reducing, wavelength shifting and colorattenuating.
 33. The light bulb of claim 1, wherein the first region isdiffusive, and the second region is specularly transmissive or lightredirecting.
 34. The light bulb of claim 1, wherein the first region isreflective, and the second region is specularly transmissive or lightredirecting.
 35. The light bulb of claim 1, wherein the first region isreflective and the second region is diffusive.
 36. A light bulb,comprising: a base configured to mechanically mount the light bulb andreceive electrical power; a light source electrically coupled to thebase; a light guide having opposed major surfaces, a light input edge,and a distal edge opposite the light input edge, wherein the light guideis coupled to the base and arranged to receive light from the lightsource at the light input edge, the light propagating along the lightguide by total internal reflection, and at least some of the light isextracted from the light guide through at least one of the majorsurfaces, light not extracted through the at least one of the majorsurfaces incident on the distal edge, the distal edge comprising a firstdistal edge region through which incident light exits the light guideand a second distal edge region; and an optical adjuster having asurface juxtaposed with the distal edge of the light guide, the opticaladjuster having a first adjuster region and a second adjuster region, atleast the first adjuster region having a light modifying characteristic,the optical adjuster and the first distal edge region variablypositionable relative to one another to selectively apportion lightemitted from the first distal edge region between the first adjusterregion and the second adjuster region, the light apportioned to thefirst adjuster region being modified by the light modifyingcharacteristic thereof so that a characteristic of the light output fromthe light bulb is modified based on relative positioning of the opticaladjuster and the first distal edge region.
 37. The light bulb of claim36, wherein the light modifying characteristic of the first adjusterregion is reflective and light exiting the light guide through the firstdistal edge region and incident on the first adjuster region isreflected back into the light guide, the reflected light propagatingalong the light guide toward the light input edge.
 38. The light bulb ofclaim 37, wherein the second distal edge region is reflective, lightincident on the second distal edge region being reflected andpropagating along the light guide toward the light input edge.
 39. Thelight bulb of claim 36, further comprising a heat sink thermally coupledto the light source.
 40. The light bulb of claim 36, wherein the lightsource is a solid-state light source.
 41. The light bulb of claim 36,wherein the light guide is a cylinder and the optical adjuster is aring.
 42. The light bulb of claim 36, wherein the light modifyingcharacteristic of the first adjuster region is at least one ofreflective, diffusive, light redirecting, polarizing, reflectivepolarizing, intensity reducing, wavelength shifting and colorattenuating.
 43. The light bulb of claim 42, wherein the second adjusterregion is specularly transmissive or has a light modifyingcharacteristic different than the first adjuster region and that is atleast one of reflective, diffusive, light redirecting, polarizing,reflective polarizing, intensity reducing, wavelength shifting and colorattenuating.
 44. The light bulb of claim 36, wherein the first distaledge region has a light modifying characteristic being at least one ofreflective, diffusive, light redirecting, polarizing, reflectivepolarizing, intensity reducing, wavelength shifting and colorattenuating.